Two-part electrical couplings for electrical lines commonly have a plug with a pair of conductor terminals mating with the pair of terminals of a receptacle. In high voltage electrical couplings there is a danger of arcing between two terminals in the coupling and insulative sleeves may be used around one or both pairs of terminals. At high voltages arcing may still occur along indirect air or moisture paths formed outside the insulation and it is the object of this invention to eliminate such indirect arcing between insulated terminals.